JP2001520463A - Etching chamber cleaning method - Google Patents

Abstract

(57) Abstract: An apparatus (20) and process for treating and conditioning an etching chamber (30) and cleaning thin and non-uniform etching residues on walls (45) and components of the etching chamber (30). is there. In the etching step, the substrate (25) is etched in the etching chamber (30), depositing a thin layer of etching residue on the walls in the chamber and on the surface of the component. In the cleaning step, a cleaning gas is introduced into the remote chamber (40) near the etching chamber (30), and microwave or high-frequency energy is applied into the remote chamber to form an active cleaning gas. A short jet of active cleaning gas at a high flow rate is introduced into the etching chamber (30) to clean the etching residues on the walls (45) and components of the etching chamber. The method comprises the steps of chemically treating a ceramic surface in a chamber containing aluminum nitride, boron carbide, boron nitride, diamond, silicon oxide, silicon carbide, silicon nitride, titanium oxide, titanium carbide, yttrium oxide, zirconium oxide, or a mixture thereof. It is particularly useful when cleaning chemically deposited etching residues.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

【Technical field】

The present invention relates to an etching chamber, and to a method for etching a substrate, cleaning and conditioning a surface of the chamber.

[0002]

[Background Art]

In the manufacture of integrated circuits, layers of silicon dioxide, polycrystalline silicon, tungsten silicide, and metal on a substrate are etched in a predetermined pattern to form gates, vias, contact holes, and interconnect lines. The etching process uses a conventional photolithographic method to form a patterned masking layer or photoresist layer on the substrate, such as an oxidized hard mask, and exposes exposed portions of the substrate to electrostatic or induced Etched by combined plasma. Commonly used etchant halogen gases include fluorinated gases such as CF ₄ , SF ₆ and NF ₃ , chlorinated gases such as Cl ₂ , CCl ₄ , SiCl ₄ and BCl ₃ , HBr, Br, CH _It contains brominated gas such as 3Br.

In an etching process, an etching chamber is contaminated by a thin layer of etching residue that deposits on walls and other components in the chamber. The composition of the etch residue layer depends on the etchant gas, the material being etched, and the composition of the mask layer applied to the substrate. When etching silicon,
A silicon-containing gas species vaporized or sputtered from the substrate is in the chamber environment;
And when etching metal species, metal ions are in the chamber environment.
The resist or mask layer on the substrate may be partially etched using an etchant gas to form gaseous hydrocarbon or oxygen species in the chamber. These different species combine within the chamber environment to form a polymerization byproduct containing hydrocarbon, elemental silicon or metal species, often also containing oxygen, nitrogen, or boron. Polymerization by-products deposit as thin layers of etch residue on chamber walls and components. The composition of the etch residue layer can vary widely throughout the chamber, depending on the composition of the locally defined gaseous environment.

[0004] Periodic cleaning of the non-uniform etch residue layer formed during the etching process to prevent contamination of the substrate and to provide an internal chamber surface with uniform and uniform chemical composition and surface features. Must. Otherwise, the etching characteristics of the etching process performed in the chamber may change significantly. In a conventional wet cleaning process, a technician must periodically shut down the etcher and scrub the walls of the chamber with an acidic chemical or solvent.
In the highly competitive semiconductor industry, the increased cost per substrate caused by etch chamber downtime is undesirable. Also, since the wet cleaning process is performed manually by a technician, it often differs from one session to another, which limits the productivity of the etching process performed in the chamber.

[0005] Another commonly used etch chamber cleaning method uses an in-situ ionized plasma generated inside the etch chamber to clean the chamber walls. However, in-situ ionized plasma species are so powerful that they rapidly erode the chamber walls and chamber components. The periodic replacement of corroded parts and components in the chamber is very expensive. Also, surface erosion of chamber surfaces and components by strong plasma species often causes instability and lack of reproducibility of subsequent plasma etching process steps performed in the chamber. For example, changes in the concentration, type, or surface function on the exposed surfaces of the walls and components in the chamber will affect the gas and the sticking coefficient of the gas on these surfaces and, as a result, the gas plasma in the chamber It also affects the etching chemistry. Chamber surfaces with excessively active surface functional groups can dramatically reduce the concentration of gaseous species required to etch a substrate. In addition, the relatively high plasma power levels required to achieve acceptable cleaning values damage system components and create residual by-products that have no alternative but to physically wipe the interior surfaces of the chamber. Tend. For example, NF ₃ plasma used to clean aluminum chamber surfaces forms Al _X F _Y compounds that cannot be etched by non-chemical processes. As another example, the use of NF ₃ gas to clean a Si ₃ N ₄ CVD deposition apparatus forms an N _X H _Y F ₂ compound, which is deposited on an evacuation pump or vacuum pump and which is not reliable. Affect.

In a chemical vapor deposition (CVD) process, a cleaning gas that is activated by microwaves in a remote chamber and energized in the CVD chamber by an inductively coupled plasma in-situ passes through these chambers. Has been used to clean a relatively thick and uniform CVD deposited layer. In conventional CVD processes, a reactive gas is used to deposit a layer of a material such as aluminum or silicon dioxide on a substrate. During this deposition process, the CVD deposits formed on the chamber walls and surfaces are often deposited as thick CVD layers on the substrate. The CVD deposit further contains a relatively constant and uniform compound associated with the material deposited on the substrate. Thick, chemically uniform CVD deposition
It can be cleaned by high-power microwave or electrostatically-coupled plasma. This example is described in U.S. Patent No. 5,449,411, which is also referred to herein. In another example, in commonly assigned European Patent No. 555 546 A1
No. is discloses a CVD silicon, the removal of the silicon deposits from NF ₃ or CF ₄ / O ₂ microwave plasma used for the walls of the CVD chamber. Similarly, German Patent No. 4,132,559 A1 also describes a method of cleaning a CVD deposition chamber using a remotely generated microwave plasma of NF ₃ .

However, CVs for thick, stoichiometrically uniform CVD deposits in the chamber
The D-chamber cleaning process is not suitable for cleaning thin, different compound etch residue layers formed on the interior surfaces of the etching chamber. The thin etch residue layer makes it difficult to stop the cleaning process after removing the residue layer, resulting in extensive corrosion of the underlying chamber surface. Also, the varying stoichiometry and composition of the etch residue layer at different locations in the chamber makes it difficult to clean all residues. For example, the etch residue formed near the chamber inlet or exhaust may be thinner than the etch residue formed near the substrate and containing a higher concentration of polymerized or oxidized mask species, and the etchant gas species (or The concentration of the material to be etched) is high. Etching residues of various stoichiometric compositions without corroding the chamber walls below the thin, flexible residue layer, or conversely, leaving the thick, chemically hard residue layer uncleaned It is very difficult to generate a plasma or gas that can uniformly etch the gas. For these reasons, conventional methods of cleaning CVD deposits in a deposition chamber include:
It is ineffective for cleaning ultra-thin and differently-composited etching residue layers formed on the walls and components of the etching chamber without damaging or corroding the underlying walls and component surfaces.

[0008] Accordingly, a process that maximizes the chemical reaction between the active cleaning gas and the etch residue in the chamber and minimizes the reactivity of the cleaning gas with the exposed surface in the chamber is desirable. Further, a method of treating an etch chamber that removes chemically attached etchant deposits from chemically active surfaces in the chamber and restores the intrinsic chemical reactivity and surface functional groups of these surfaces is further desirable.
It is also desirable to have a chamber cleaning process that removes etch residues of varying thickness and non-uniform stoichiometry without excessively corroding the chamber walls and components.

[0009]

Summary of the Invention

The present invention etches a substrate in an etching chamber and removes a non-uniform, different composition etch residue layer from the etching chamber walls and components to provide a stable and reproducible etching performance. , An apparatus and method for treating and conditioning a ceramic surface in a chamber. During the etching step, the substrate is etched in the etching chamber, whereby a thin layer of etching residue is deposited on walls and surfaces of components in the etching chamber. In the cleaning step, the cleaning gas is activated in the remote chamber adjacent to the etching chamber, for example by applying microwave or radio frequency energy into the remote chamber. This active cleaning gas is introduced into the etching chamber to clean etching residues on walls and components within the etching chamber. The method comprises a method for stubbornly attaching to a ceramic surface containing aluminum nitride, boron carbide, boron nitride, diamond, silicon oxide, silicon carbide, silicon nitride, titanium oxide, titanium carbide, yttrium oxide, zirconium oxide, or a mixture thereof, Alternatively, it has been found to be particularly useful for cleaning etching residues that undergo a chemical reaction with the surface.

When etching certain materials, such as silicon-containing layers, a relatively thin etch residue layer containing primary polymerization, oxygen, and silicon-containing species and having a thickness of about 0.01 to about 1 micron is obtained. Formed on chamber walls and surfaces. Such an etchant layer provides a short jet of a high flow of active cleaning gas, with a volume of about 40,000.
It has been found that removal can be effectively accomplished by introducing a flow rate F ^R equal to about 200 to about 2000 sccm for a 0 cm ³ chamber into the etching chamber for about 0.5 to about 100 seconds.

In order to increase the throughput from the etching chamber, it is preferable to perform the cleaning process while the substrate is being transported out of the etching chamber or immediately after the substrate is transported. Also, in order to clean and condition the surfaces in the chamber without corroding the chamber surface or the substrate surface, a high flow rate of active cleaning gas may be applied while the substrate is being transported into or out of the chamber. Preferably, a short jet is introduced into the etching chamber for a short time. Next, another substrate is introduced into the chamber, and the etching, transporting, cleaning and conditioning steps are repeated until the supply of the substrate is completed. In a preferred form, the remote chamber is maintained at a higher pressure than the etch chamber to provide more laminar flow of the cleaning gas along the sidewalls and surfaces of the chamber.

Further, in accordance with another aspect of the invention, good cleaning and conditioning of the etching chamber surface that is highly reactive with etching residues introduces an active gas into the chamber in a plurality of discrete steps. Know that this can be achieved. The multi-cycle conditioning process includes: (i) introducing a first active cleaning gas formed by maintaining a gas activator in the remote chamber at a first power level into the etching chamber; At least one second step is provided for introducing a second active cleaning gas, formed by maintaining the gas activator in the chamber at a second power level different from the first power level, into the etching chamber. The cleaning gas in the first stage contains more decomposed and more reactive species that can remove hard and thick etching residues on the chamber walls and components near the substrate. The cleaning gas in the second cleaning stage is activated at a lower power level to treat and condition surfaces such as ceramic surfaces more gently. The duration of each washing step is from about 0.5 to about 100
Seconds, more preferably from about 0.5 to about 24 seconds. The multi-cycle process can be repeated a sufficient number of times to treat the walls of the chamber and attenuate the concentration of etch residues to a desired level.

In another aspect, the present invention provides a process gas inlet for introducing a process gas into an etching chamber, a plasma generator for forming a plasma from the process gas to etch a substrate, The present invention relates to an etching apparatus provided with an etching chamber provided with an exhaust system for exhausting air from an etching chamber. A remote chamber adjacent to the etching chamber is used to generate the active cleaning gas. The gas distribution system includes: (i) a gas conduit for transporting the active cleaning gas from the remote chamber to the etching chamber; and (ii) directing a flow of the active cleaning gas substantially parallel to one or more interior surfaces of the chamber. And (iii) a gas flow regulator for regulating the flow of the active cleaning gas into the gas flow distributor. The gas flow distributor directs the flow of the active cleaning gas to these areas to preferentially remove the thicker etch residue layer without corroding portions of the chamber having the thinner etch residue layer. ,
Preferably, there is provided a nozzle located adjacent to a surface in the chamber having a thick layer of etching residue.

[0014] These and other features, properties, and advantages of the present invention will be more clearly understood from the drawings, description, and appended claims, which illustrate examples of the present invention. The description and drawings shown below are:
It illustrates illustrative features of the present invention, each of which can be used generally in the present invention, not merely in the context of a particular drawing, and Includes any combination of these features.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

Apparatus 20 is suitable for etching a substrate 25 according to the present invention, as schematically shown in FIG. 1, and forms a sealed injection chamber 30 defining a process zone for processing the substrate, forming an active cleaning gas. The remote chamber 40 includes a load lock transfer area (not shown) maintained at a low pressure for holding a cassette of substrates. A particular embodiment of the apparatus 20 shown here is the semiconductor substrate 2
5 and is provided only to illustrate the present invention and should not be used to limit the scope of the present invention. Special features of the device 20 include:
U.S. patent specification filed Feb. 2, 1996, Ser. No. 08 / 597,445.
"RF Plasma Reactor with Hybrid Conductor and Multi-Radius Dome Ceiling", US Patent Specification filed February 15, 1993, application number 08 / 389,88.
This is described in No. 9. These specifications are referenced herein.
The sealed injection chamber 30 includes a side wall 45 and a bottom wall 50 made of one of a variety of materials, including metals, ceramics, glass, polymers, and composites. The process zone defined in the etching chamber 30
Directly above and surrounding it, and having a volume of at least about 10,000
cm ³ , more preferably from about 10,000 to about 50,000 cm ³ . Metals including aluminum, anodized aluminum, "HAYNES 242", "Al-6061", "SS 304", "SS 316", INCONEL are commonly used to produce a sealed injection chamber 30; Among them, anodized aluminum oxide is preferred.

The process zone comprises a flat, rectangular, arcuate, conical, dome-shaped or multi-radius dome-shaped ceiling 55. In order to increase the decomposition of the etchant gas in the plasma zone, the sealing 55 is preferably dome-shaped so that the plasma source power can be distributed uniformly over the entire volume of the plasma processing zone. An example of this is U.S. Patent Application Ser. No. 08 / 596,960, filed Feb. 5, 1996, entitled "Plasma Procedures for Etching Multicomponent Alloy."
s ". This is referred to herein. The dome-shaped ceiling 55 reduces the recombination loss of decomposed ions near the substrate 25, thereby reducing the flattened ceiling. The density of the plasma ions is constant over the entire substrate, because ion recombination losses occur near the ceiling 55, and the dome-type ceiling has a longer distance from the center 60 of the substrate than a flat ceiling. The dome-shaped ceiling 55 has a prana (ie, flat dome), conical shape,
It may be frusto-conical, cylindrical, or other combinations of these shapes that provide a dome-shaped surface on the substrate 25.

Through a distribution system 65 including a process gas supply 70 that operates a gas flow meter 80 and a gas flow control system 75, process gas is injected into the injection chamber 30.
Introduced within. The gas distribution system 65 may be attached to the gas outlet 85 located around the substrate 25 (as shown) or to the sealing of the injection chamber 30.
A shower head with an outlet inside (not shown) can also be provided. Consumed process gas and etchant by-products are pumped 90 (typically including a 1000 l / s roughing pump) capable of achieving a minimum pressure of about 10 ⁻³ mTorr in the injection chamber 30. Is exhausted from the process chamber 30 via A throttle valve 95 is provided in the exhaust unit 90 to control the flow of the consumed process gas and the pressure of the process gas in the chamber 30. Preferably, the gas is forced out of the chamber 30 using an asymmetric pumping channel 100 to distribute the gas more symmetrically and uniformly across the surface 105 of the substrate.

A plasma is formed from the process gas introduced into the chamber 30 using a plasma generator 110 that couples the electric field into the process zone of the chamber. A suitable plasma generator 110 includes an inductor comprising one or more inductor coils extending through the center of the process chamber 30 and having a circular symmetry with a central axis coincident with a vertical axis perpendicular to the plane of the substrate 25. An antenna 115 is provided. The inductor antenna 115 preferably has 1 to 10 turns, more generally 2 to 6 turns. Providing a strong inductive flux connection with the proximity coupling with the plasma, as described in US patent application Ser. No. 08 / 648,254, which allows higher plasma ions in the plasma zone near the substrate 25. To obtain the density, the device and multiple solenoid cells are selected to provide a product with the desired current and antenna turn (d / dt) (N = 1) near the ceiling 55. If the inductor antenna 115 is located near the dome ceiling 55, the ceiling of the chamber 30 is shaped like a machined silicon dioxide plate or curved, transparent to high frequency fields. For example, a dielectric material such as a silicon or silicon dioxide tile bonded to one another.
Preferably, the inductor coil 115 surrounding the perimeter of the sidewall 45 of the process chamber 30 has a “flat”, which increases the plasma ion density directly toward the substrate center 60 because the ion density is affected by local ionization near the inductor coil 115. This is a dome-shaped multi-radius dome-shaped inductor coil, and the multi-radius inductor coil is preferably closer to the substrate center 60 than the hemispherical coil. In another preferred embodiment, the ceiling 55 comprises a multi-radius dome having at least a central radius R and a corner radius r, where r is less than the central radius R and R / r is about 2 to about It is 10.

Further, the plasma formed in the plasma zone can be expanded using a magnetically expanded reactor. Here, a magnetic field generator (not shown) such as a permanent magnet or an electromagnetic coil is used to apply a magnetic field to the plasma zone to increase the density and uniformity of the plasma. As described in U.S. Pat. No. 4,842,683, filed Jun. 27, 1989, which is incorporated herein by reference, the magnetic field is generated by a magnetic field rotating parallel to the plane of the substrate 25. Preferably, a rotating magnetic field having an axis is provided. The magnetic field in chamber 30 is strong enough to increase the density of ions formed in the plasma and uniform enough to reduce charge-up damage to features such as CMOS gates. Generally, the surface 10 of the substrate
The magnetic field measured on 5 is less than 500 Gauss, more typically from about 10 to about 100 Gauss, and most typically from about 10 Gauss to about 30 Gauss.

In addition to inductor antenna 115, one or more process electrodes can be used to accelerate or energize plasma ions in chamber 30. The process electrode has a first electrode 120. The first electrode forms a wall of the process chamber 30, for example, the ceiling 55 and / or the side wall 45 of the chamber. First electrode 120 is electrostatically coupled to second electrode 125 below substrate 25. An electrode voltage supply 155 supplies a high-frequency potential for maintaining the first electrode 120 and the second electrode 125 at different potentials. The frequency of the high frequency voltage applied to the inductor antenna 115 is generally about 50 KHz to about 60 MHz,
More typically, it is about 13.56 MHz, and the power level of the high frequency voltage applied to the antenna is about 100 to about 5000 watts.

The sealed chamber 30 has one or more ceramic surfaces that perform different functions. For example, in one embodiment, process chamber walls 45, 50, 5,
5 includes boron carbide, boron nitride, silicon, silicon oxide, silicon carbide, especially for protecting the wall from corrosion by chemicals such as etchant gas compounds.
It is coated with a ceramic material such as silicon nitride. For example, boron carbide can be used in a gas environment combined with fluorine to prevent corrosion from chamber sidewalls 45.
It is useful for protecting. As another example, a sapphire (aluminum oxide) gas distribution plate can be used to release the process gas into the chamber 30.

Another useful ceramic surface in the chamber is that of a single-phase ceramic member 135 having a ceramic receiving surface 140 for receiving the substrate 25 thereon. Suitable ceramic materials include one or more of aluminum nitride, boron carbide, diamond,
Silicon oxide, silicon carbide, silicon nitride, titanium oxide, titanium carbide, yttrium oxide, and zirconium oxide are included. The ceramic member 135 is about 10%
It is made from a low porosity ceramic having a lower porosity. The thermal conductivity of the dielectric material is preferably high, such as diamond or aluminum nitride, having a high conductivity of about 80 to about 240 W / mK. The second electrode 125 is embedded in the ceramic member 135 so that the ceramic material can completely surround the second electrode to form a unitary single-phase ceramic member. The second electrode is made of a conductive metal such as aluminum, copper, gold, molybdenum, tantalum, titanium, tungsten, and alloys thereof, and is further thermally sintered between the ceramic member 135 and the electrode 125 embedded therein. It is more preferable to use a high melting point refractory metal such as tungsten, tantalum, or molybdenum that allows the above. The ceramic member 135 in which the electrode 125 is embedded can be manufactured from a mixture of ceramic powder and a low-concentration organic bonding material by an equilibrium pressing method, a hot pressing method, a casting method, or a tape casting method.

The second electrode 125 embedded within the integral single-phase ceramic member 135 is a sole conductor to which a “hot” radio frequency potential is applied, and the other electrodes in the chamber are relative to the second electrode 125. , Different electrical potentials, including electrical ground or floating potential. Since the second electrode is embedded in the one-piece ceramic member 135, it need not be electrically insulated from the chamber 30 by an additional insulating shield, so that the second electrode 125 and the grounded chamber walls 45, 50 The parasitic capacitance impedance load in the chamber 30 that occurs during the period can be reduced. Furthermore, since there is no insulator shield in the chamber 30, the second electrode 125 is provided with a wider active electrode area than a conventional cathode to cover the area having a diameter that extends throughout the chamber bottom 50. The active range can be increased. The second electrode 125 also functions as the electrostatic chuck 145. The electrostatic chuck is
The substrate 25 is electrostatically applied to the receiving surface 140 of the ceramic member 135 using a DC chucking voltage applied via an electrical conductor 150 inserted through the ceramic member 135 to connect to the second electrode 125. Generates an electrostatic charge for holding.

The first electrode 120 and the second electrode 125 include an AC voltage supply 160 that supplies a high-frequency voltage generated by plasma to the second electrode 125 and a DC voltage supply 165 that supplies a chucking voltage to the electrode 125. Are electrically biased to each other by an electrode voltage supply 155 including AC voltage supply 160 may be used to form one or more 13.56 MHZ to 40 to form an electrostatically coupled plasma within chamber 30.
It supplies a high frequency which emits a voltage having a frequency of 0 KHz. The power level of the high frequency bias current applied to electrode 125 is typically between about 50W and about 3000W. In order to form an electrostatic charge holding the substrate 25 on the chuck 145, the electrode 125
Is applied with another DC voltage. The high frequency power is coupled to a bridge circuit, an electrical filter, to provide DC chucking power to the electrodes 126.

The etching apparatus 20 further includes a remote chamber 40 such as a quartz tube. The remote chamber is located near the process zone of the etching chamber 30,
It is connected to this via a gas line 170. The remote chamber 40 includes a gas activator 175 used to supply microwave or radio frequency energy into the chamber 30 to activate the cleaning gas by ionization or decomposition. When supplied with microwave energy, the cleaning gas is decomposed to form unloaded atoms. For example, Cl ₂ decomposes to form chlorine. When high frequency energy is applied to the remote chamber 40, for example, by inductive or capacitive coupling, the cleaning gas forms loaded and ionized species within the remote chamber.

The gas activator 175 preferably provides a microwave that chemically activates the cleaning and conditioning gas in the remote chamber by the formation of highly decomposed gas. In this case, the gas activator 175 comprises a microwave waveguide 180, as shown schematically in FIG. This microwave waveguide
Applied Science & Te in Woburn, Mass.
Powered by a microwave generator 185, such as the "ASTEX" microwave plasma generator available from TN. Generally, microwave generator 185 includes microwave tuning assembly 190 and 2.54
And a magnetron microwave generator 195 capable of generating microwaves at a frequency of GHz. Generally, the magnetron 195 comprises a powerful microwave oscillator. In this microwave oscillator, the potential energy of the electron cloud near the central cathode is converted to microwave energy in a series of cavities radially spaced around the cathode. The resonance frequency of the magnetron 195 is determined by the physical dimensions of the cavity of the resonator.

The second gas supply system 200 supplies the cleaning gas to the remote chamber 40 via an electronically operated valve 205 and a flow control mechanism at a flow rate selected by the user. Next, in order to generate microwaves, the microwave generator control system supplies power to the microwave generator 185, and the generated microwave is propagated by the waveguide 180 to the remote chamber 40. The active cleaning gas is propagated from the remote chamber 40 to the etching chamber 30 via a gas distribution system with gas lines. Optionally, a filter is located in line 170. By passing the active gas through a filter located in conduit 170 before entering the etching chamber 30, particulate matter formed during the activation of the reactive species is removed.
In the described embodiment, the filter is made of a ceramic material with pores of about 0.01 to 0.03 microns. In addition, Teflon (TM DuP
Materials such as ont de Nemours, polyimide, inert carbon, or sulfur can also be used. For example, the cleaning gas may include CF ₄ or SF ₆ , or other carbon or sulfur containing halogen compounds, and activated carbon of sulfur species may appear as a by-product of the activation process. Generally, it is desirable to remove such carbon or sulfur products to prevent contamination of the etch chamber environment.

Instead of microwaves, the cleaning gas can be activated using high frequency energy supplied from an electrostatic or dielectrically coupled source in or near the remote chamber 40. As shown in FIG. 4, a suitable high frequency energy type gas activator includes an inductor antenna. The inductor antenna comprises one or more inductor coils having a circular symmetry with respect to a central axis extending through the center of the remote chamber 40 and coincident with a vertical axis. Alternatively, the gas activator may include a pair of electrodes located within the remote chamber 40 to form an electrostatic coupling field within the chamber 40, as shown in FIG.

The gas distribution system further includes a gas flow distributor 215 that directs the flow of the active cleaning gas substantially parallel and adjacent to one or more internal surfaces of the chamber 30.
And a gas flow regulator 220 for regulating the flow of the active cleaning gas into the gas flow distributor 215. The gas flow regulator includes a flow control valve 205 or 225 operated by a conventional computer control system 230 to control the flow of the cleaning gas to the remote chamber 40 at a predetermined or user set gas flow rate. ing. Optionally, the carrier gas source can be connected to the remote activation chamber 40 via another valve and flow control mechanism (not shown). The carrier gas assists in delivering the active cleaning gas to the etching chamber 30 and may be any conventional gas that is non-reactive or compatible with a particular cleaning process. For example, a suitable carrier gas may be argon, nitrogen, helium, halogen, or oxygen. The carrier gas also assists in the cleaning process by initiating and / or stabilizing the activated gaseous species in the etching chamber 30.

The gas flow distributor 215 directs the flow of the active cleaning gas to one or more surfaces inside the chamber 30, generally parallel or adjacent to the surface of the chamber side wall 45, the bottom wall 50 or the surface of the component. Orient. By directing the flow of the cleaning gas substantially parallel to certain chamber surfaces, a more concentrated laminar flow of the cleaning gas can be provided near these surfaces, removing etch residues and removing the chamber surface. Can be handled and adjusted more effectively. In the embodiment shown in FIG. 3, the gas distributor comprises a plurality of gas injection nozzles 2 arranged symmetrically around the central axis of the chamber 30.
35a, b, and c. These nozzles provide a layer of gas immediately adjacent to and near the surface of and substantially parallel to the surface of the etching chamber 30 to better remove etching residues remaining on the chamber walls. It is for providing a flow curtain. The gas injection nozzles 235a, b, c are highly condensed and thick, and have less residue along the walls and surfaces of the chamber where the more chemically synthesized etch residues remain. Provide a cleaning gas flow pattern or flow path that is directed to preferentially clean and condition residual surfaces while excessively corroding portions.

In another embodiment shown in FIG. 4, the gas distributor 215 includes one or more gas injection nozzles 23.
5, which nozzle is located in the chamber 30 behind the gas diffusion or flow redirecting plate 240. The gas diffusion plate 240 is symmetrically disposed within the chamber, preferably about a vertical central axis substantially aligned with the central axis of the chamber 30. Plate 240 covers gas injection nozzle 235 and the flow of cleaning gas emitted from injection nozzle 235 in a groove defined between plate 240 and a parallel portion of the surface near plate 240 of the chamber. And deflect it again. The gas expansion plate 240 is spaced a predetermined distance from the chamber surface to define a groove of a predetermined height. The cleaning gas is exhausted from the annular and ring-shaped outlets defined by the plate 240 and the chamber surface substantially parallel to the chamber surface and flows into the layer flow path along the surface of the etching chamber wall.

In yet another embodiment, shown in FIG. 5, the gas distributor 215 includes injection nozzles 235 a, b at the end of the channel 250. These nozzles are arranged symmetrically around the central axis of the chamber 30. An annular ledge 255 is positioned spaced apart from a portion of the channel 250 to form a circumferential collar that directs the flow of the cleaning gas along and through a particular surface of the chamber 30,
It covers a part of. This provides reconditioning and treatment of these surfaces. In the configuration using the gas plate of FIG. 4, the channel 250 provided near the chamber surface is provided.
An annular opening provides a forced flow of cleaning gas through the chamber surface.

The gas flow distributor 215 preferably comprises a gas injection nozzle 235 located in the chamber 30 near the surface where the thick layer of etch deposits is deposited.
These nozzles 235 are used to direct the flow of the active cleaning gas to these areas in order to preferentially remove a thicker layer of etch residue without corroding the thinner layers of the chamber 30. Things. This is particularly beneficial for processes and etch chambers that produce a wide range of synthetic or thick etch residue deposit layers over the surface of chamber 30. In general, the thicker the etch residue is deposited near the substrate, where more resist or mask evaporates from the substrate and solidifies on the chamber surface. For example, in the preferred embodiment shown in FIG. 6, the gas injection nozzles 235a, b surround the substrate 25 and are located in a circle extending from the bottom wall 50 of the chamber 30. This configuration is preferred for etching processes where a large amount of etching residue is formed near the surface of the chamber located adjacent to the substrate, since the etching residue is a solidified by-product of the resist or oxidation mask on the substrate. Similarly, the gas injection nozzle 23
5a, b can also be located in another part of the chamber 30. The location where the nozzles are located is determined for each type of each process from the distribution and etching residues across the chamber surface.

[0034]

【Etching process】

Next, the operation of the etching chamber 30 for etching one or more silicon contact layers on the substrate 25 will be described with reference to the flowchart of FIG. Generally, substrate 25 comprises a semiconductor material, such as a silicon or gallium arsenide wafer, and a plurality of layers formed thereon. The layers on the substrate 25 are, for example, a lower layer of silicon oxide that functions as a gate oxide layer for MOS transistors and a layer of polycrystalline silicon or patterned polycide (combination of tungsten silicon and the underlying polycrystalline silicon layer). It has an upper layer. Generally, the thickness of each layer is from about 100 nm to about 350 nm. DuPont de Nemou
A mask layer or oxidized hardmask, such as RIS Chemical's "RISTON" photoresist is applied over substrate 25 to a thickness of about 0.4 to about 1.3 microns, using a conventional photolithographic process. Thus, features etched in the layer are defined. Exposed portions between the mask layers are etched to form features. This feature is, for example, a contact hole for assembling a gate electrode for a MOS transistor; a polycide interconnection feature commonly used as a gate electrode; diffused through these to insulate a silicon oxide / nitride layer. A multilayer metal structure used to electrically connect two or more electrically conductive layers.

To carry out the process of the present invention, the substrate 25 is transferred from the load lock chamber to the transfer chamber via the slit valve and into the chamber 30 using the robot arm 257. The lift finger device (not shown) includes a lift finger that extends through a lift finger opening provided in the chuck 145 for receiving the substrate 25 or lifting the substrate 25 from the chuck 145. To extend approximately 2 to 5 cm above the surface of chuck 145, robot arm 257 places substrate 25 at the tip (not shown) of the lift finger lifted by the air lift mechanism. The pneumatic mechanism lowers the substrate 25 onto the electrostatic chuck 145 under the control of the computer system, and helium is supplied into the chuck through the opening 265 to control the temperature of the substrate 25.

An etchant gas is introduced into the chamber 30 via the gas outlet 85, and typically the chamber is in a range from about 0.1 to about 400 mTorr, more typically about 0.
It is maintained at a pressure in the range of 1 to 80 mTorr. Halogen-containing etchant gases suitable for etching the substrate 25 include, for example, HCl, BCl ₃ , HBr, Br ₂ , Cl ₂ , CCl ₄ , SiCl ₄ , SF ₆ , F, NF ₃ , HF, CF ₃ , CF ₄ , C
_{H 3 F, CHF 3, C} 2 H 2 F 2, C 2 H 4 F 6, C 2 F 6, C 3 F 8, C 4 F 8, C 2 HF 5,
_{C 4 F 10, CF 2 Cl} 2, CFCl 3, also mixtures thereof. The etching process of the present invention provides a high etching rate and a highly selective etching of the silicon layer on the substrate 25. Preferred compositions include (i) chlorine, (ii) hydrogen bromide, and optionally (iii) helium oxygen gas. To form volatile SiCl _x species that are exhausted from chamber 30, chlorine gas is ionized to form atomic chlorine and chlorine containing species that etch the metal silicide or polysilicon layer. The chlorine gas can include Cl ₂ , or other chlorine-containing gases equivalent to chlorine, such as HCl, BCl ₃ , or mixtures thereof. Hydrogen bromide gas accelerates the etch rate of the polycrystalline silicon layer, while at the same time attenuates the etch rate of the resist layer to increase the etch selectivity. Helium oxygen gas forms species and ions in the excited state, further promoting the etch ratio and etch selectivity.

Referring now to FIG. 2, an induced electric field is formed in the chamber 30, and the first and second electrodes 120 and 125 are biased in the chamber to form the plasma generator 11.
The energy is applied to the plasma from the etchant gas using zero. The plasma is formed by applying a high frequency source current to the inductor antenna 115 and applying a high frequency bias voltage to the electrodes 120,125. The etchant gas is ionized in an applied electric field to form neutrals with halogen-containing ions that react with the silicon-containing layer on substrate 25 to etch the layer and form volatile gas species that are exhausted from chamber 30. I do. To anisotropically etch the silicon-containing layer with high selectivity in relation to the overlying mask layer, the source current power level (to the inductor antenna 115) versus the bias voltage power level (to the process electrodes 120, 125) power ratio P ₁ of) is selected to enlarge the etchant plasma capability. Increasing the source power level of the current applied to the inductor antenna 115 increases the etchant species that are decomposed in the plasma and provides better isotropic etching. On the other hand, the process electrode 120
, 125, provides a higher impact energy configuration to the plasma ions, thereby increasing the degree of anisotropic etching. It has been found that an excessively high power ratio P ₁ causes sputtering of the substrate 25, resulting in non-uniform etching of the substrate. On the other hand, an excessively low power ratio P ₁ causes insufficient decomposition of the etchant gas into the decomposed ions, resulting in a reduced etch rate and reduced etch selectivity. The preferred power ratio P ₁ is at least about 2: 1 and more preferably from about 2: 1 to about 20: 1. A plasma is formed by applying a source power current of about 400 to about 3000 W level to the inductor antenna 115 and surrounding the plasma zone 35, and applying a power level of about 20 to about 1000 W to the process electrode in the plasma zone. The plasma ions are attracted toward the substrate 25 by adding to them.

In order to stop the etching process without etching past the underlying layers on the substrate, the substrate 25 etching process is generally performed in a main etching stage and an “over-etching” stage. The main etching step is stopped before the upper layer is completely etched, and an over-etching step is performed to perform the etching through the residual portion of the upper layer. In order to obtain a slower, more controllable etch rate, the halogen content of the etchant gas is generally reduced during the overetch step. For example, the main etch process steps suitable for etching the polycrystalline silicon layer, the content of Cl ₂ is 68Sccm, the content of H Br can 112Sccm, the content of the He-O ₂ is able to use the etcher Ntogasu of 16sccm it can. The power level of the source current applied to the inductor antenna 115 is 475 W, the power level of the source current applied to the process electrodes 120 and 125 is 80 W, and the power ratio P ₁ is about 6: 1. The pressure in chamber 30 is maintained at 4 mTorr. An over-etch process step suitable for the polycrystalline silicon layer is 158 scc at a chamber pressure of 50 mTorr.
m is for the use of the etchant process gas having HBr and 10sccm of He-O _2. In the over-etching process stage, the power level of the source current applied to the inductor antenna 115 is 1000W and the process electrodes 120, 12
Since the power level of the bias voltage applied to 5 was 100W, the power ratio P ₁ is about 10: a 1.

The end-of-etch process or the end of etching of a particular layer is determined by measuring the change in emission at a particular wavelength associated with a detectable gaseous species using a photo-endpoint measurement technique. I do. A sharp decrease or increase in the concentration of the selected detectable species indicates that one or more layers have been etched. For example, a sharp increase in the concentration of the silicon species (which occurs due to a chemical reaction between the process gas and the underlying polycrystalline silicon) indicates that the etching process has been terminated and that the chloride ion concentration has increased. In some cases (which occurs due to reduced underlayer corrosion), it indicates that the metal silicide layer etch is complete and begins to etch the underlayer.

At the end of the process, an air lift device 270 is used to lift the substrate 25
The lift pins are lifted through the electrostatic chuck 145, and the robot transfer arm is inserted between the substrate 25 and the chuck to lift the substrate from the lift pins. Thereafter, the lift pins are pulled into the chuck 145, and the robot arm
Out of the etching chamber 30 and transported into a transfer chamber maintained in a vacuum environment.

[0041]

[Cleaning and adjustment process]

Thereafter, a processing process is used to treat and recondition the interior surfaces of the etching chamber 30, particularly the ceramic surface, to clean the etching residues formed on the chamber walls 45, 50, 55 and components. The etching residue is deposited inside the surface of the etching chamber 30, for example, the side wall 45, the single-phase ceramic member
5 and deposits on and reacts with the chamber sealing 55 to form a hard, chemical resistant layer. Typically, the etch residue comprises halogen, carbon, hydrogen, oxygen, and / or a silicon compound polymerized organic compound formed during etching of the substrate 25. In particular, the etch residues react with ceramic surfaces of chamber 30, such as single phase ceramic member 135, having a high reactive surface functional group. For example, a ceramic surface containing silicon or silicon oxide has a Si-OH 'surface group that is formed when the ceramic surface is exposed to air, oxygen, or ambient moisture, and may include aluminum oxide or aluminum nitride. The surface comprises an Al-OH 'surface group. These surface functional groups react chemically with the etching residues to form a hard, adhesive coating on chamber surfaces or components.

The chamber processing process eliminates and reduces the adverse effects of reaction by-products of the etching residue deposited on the chamber 30 and the chamber surface. This will be described. In order to carry out the process, the etchant gas is exhausted from the process chamber 30 by fully opening the throttle valve 95 of the exhaust system 90. A cleaning gas such as NF ₃ , CF ₄ , SF ₆ , C ₂ F ₆ , CCl ₄ , C ₂ Cl ₆ , or a mixture thereof is introduced into the remote chamber 40, where, for example, a microwave generator 185 enters the remote chamber. Activated by applied microwaves or by high frequency energy applied via electrodes or inductor coils. Thereafter, an active cleaning gas is introduced into the etching chamber 30 to clean the etching residues in the chamber.

To achieve the two functions, the power level P _{L of the} current used to operate the gas activator 175 is selected. In the first function, the cleaning gas must undergo a chemical reaction with a thin layer of carbon, trapped halogen species, silicon, and / or halogen species etching residue formed on the chamber surface and must be vaporized. The flow rate F _{R of the} cleaning gas and the power level P _L of the gas activator 175 control the ratio of decomposed species to non-decomposed species in the active cleaning gas. The more decomposed gas species will preferentially react with the thin etchant layer associated with the lower chamber layer. This is why the active plasma can remove a thin layer of etching residue formed on the chamber walls while minimizing corrosion of the underlying chamber surface. In a second function, after removing the etching residues, an active cleaning gas is applied to the chamber 30.
Recondition the surface inside, especially the ceramic surface. It has been found that halogen-containing etching residues are very susceptible to chemical reactions with the chamber walls 45, 50, 55 and components. In particular, the etching chamber 30
Chemical reactions are more likely to occur if the ceramic surface has a high reactive surface functional group, such as i-OH ', Al-OH' and other similar species. For example, the fluorine-containing species etch residue within, in order to form the AlF ₃ one volatile, rapidly corrode the oxide or nitride ceramic aluminum surface. Similarly, bromine-containing species hydrolyze in ambient moisture to form hydrogen oxide bromide.
This hydrogen oxide bromide corrodes silicon-containing components. These types of etch residues must be quickly removed from chamber 30 to prevent excessive corrosion of the chamber surface. Activated gas species with a high flow rate F _R and a low power level P _L condition the chamber surface. That is, at least a portion of a surface functional group such as an AlOH 'group on the ceramic surface in the chamber 30 is repaired. This returns the chemical state of the chamber surface to its original chemical state, restoring the surface to its initial surface activity and function in preparation for the next etching process. As a result, the etching process performed in the processed chamber 30 produces more reproducible results than chambers using a wet or RIE cleaning process to clean the chamber.

The flow rate F _{R of the} cleaning gas and the power level P _{L of the} current applied to the gas activator 175 such as the microwave plasma activation device 185 are preferably selected as shown below. Etching residues on the etching chamber surface,
The vapors can be vaporized to a concentration low enough to have no effect on the contamination of the chamber gas mixture and the substrate without corroding the walls and components within the chamber 30. The flow rate F _{R of the} cleaning gas must be high enough to react with substantially all of the etching residue on the ceramic surface to form gaseous by-products. However,
Excessive flow rates can cause corrosion of chamber walls and surfaces due to constant exposure to activated gaseous species in the cleaning gas.

For example, when etching a silicon-containing layer on a substrate, a relatively thin etch residue having a thickness of about 0.01 to 1000 microns, including primary polymerization and silicon-containing species, forms chamber walls 45, 50,. 55 and have been found to form on the surface. This etch residue layer introduces a high frequency active cleaning gas into the chamber 30 at a flow rate of about 200 to about 2000 sccm suitable for a chamber having a volume of about 40,000 cm ³ for about 0.5 to 100 seconds. Then, by cleaning the etching residue, the walls and components in the chamber can be substantially removed without corrosion. For process chambers of different sizes, the chamber volume (
An equivalent flow rate of the cleaning gas mixture should be used that maintains the same ratio of NF ₃ flow rate (cm ³ ) to NF ₃ flow rate (sccm). While gases consisting solely of NF ₃ give excellent results, inert gases such as helium or argon can also be added to the process gas. Or a process gas, can also be prepared with a mixture of commercially available gases, such as He-O _2.

When using a gas activator 175 with a microwave generator 185, the microwave generator 18 is also a measure of the power and intensity of the microwave applied to the remote plasma chamber 40 via the gas activator 175.
The power level P _L operating 5 is also selected to clean and treat the surface of the chamber 30 without corroding the chamber walls. The power level is sufficient to provide a cleaning gas that is sufficiently reactive to remove substantially all of the etching residue on the chamber walls and components without damaging the underlying structure. Need to be high. Excessively high power level P _L occurs very activated gas species Runode, corrodes the walls of the chamber. Conversely, active cleaning gases at too low a power level cannot remove thick, chemically hard etching residues on the chamber walls and some of the components. NF ₃ cleaning appropriate power level in the gas is from about 500 to about 4000 W, more preferably from about 1500 to about 2500W.

To process and condition the chamber, the activated gaseous species may
It is introduced into the etching chamber 30. With a short burst of active cleaning gas,
Significant advantages over the cleaning process are obtained. First, by blowing out the active cleaning gas
More highly degraded species are obtained, removing etching residues and
The "light" chemical reaction process, which is performed by the chemically decomposed species each time,
The ceramic surface in chamber 30 is cleaned and conditioned. Cleaning gas ejection and
By quickly evacuating the cleaning gas from the chamber and the chamber 30, the decomposed species are recombined.
To prevent the formation of other species that corrode chamber surfaces and components
You can also. This mechanism allows reaction by-products to be re-coupled in chamber 30.
Further facilitated by the high flow rates of gas spouts that help wash off before merging
. In addition, this gas bleed out during the cleaning operation onto exposed etching residue surfaces.
Keeps a fresh supply of cleaning gas, thereby removing the residue layer at high speed. Substantive
Etch residue without corroding chamber walls and components
For cleaning, a spout of active cleaning gas is applied to a volume of about 40,000 cm.^ThreeFlow rate F at least equal to about 200 to about 2000 sccm. _R And is preferably introduced into the etching chamber for about 0.5 to about 100 seconds. In addition, the cleaning gas generated remotely is etched for about 0.5 to about 24 seconds.
More preferably, it is introduced into the chamber.

In another aspect of the invention, while transporting the substrate 25 out of the chamber, or
Immediately after the substrate 25 is removed from the etching chamber 30, the apparatus is down-timed.
Cleaning that is beneficial to reduce system and increase the throughput of etch chamber 30.
A cleaning process is performed. In this case, an active cleaning gas is provided in chamber 40.
While simultaneously transferring the substrate 25 out of the etching chamber, _R Of the active cleaning gas for a time sufficient to treat and condition the surface of the etching chamber 30 without substantially corroding the surface.
Introduced in 0. For example, when the end of the etching of the substrate 25 approaches, the cleaning gas
Inlet valve provided in gas line between supply 200 and remote chamber 40
Cleaning gas is introduced into the remote chamber 40 by opening 205,
The active cleaning gas is etched at the same time that the substrate is transported out of the etching chamber.
To flow into the chamber 30. Substrate etching
During the process, the inlet valve 205 of the remote chamber is in the closed state, and the etching is completed.
The completed substrate 25 is taken out of or transported from the etching chamber 30.
In between, ie, for example, the substrate 25 is provided on the side wall 45 of the etching chamber
While passing through the groove valve, the robot controller 259 sends the cleaning gas
Transmits a first signal to open inlet valve 205 to enter chamber 40
I do. For example, the robot control device 259
A first trigger signal can be provided to the computer control system.
, The inlet valve 205 is opened, the microwave generator 185 is activated, and the
A cleaning gas is formed. To clean and condition the surface inside chamber 30
The cleaning gas flows into the etching chamber 30 for a short time. Next, the robot
The control device 259 has the second substrate 25 to be inserted into the etching chamber 30.
The inlet valve 205 is closed when it comes, and the exhaust system 90 is connected to the etching chamber.
A second trigger signal for exhausting the remaining active gas is transmitted. afterwards,
Another substrate 25 is introduced into the chamber 30 and all substrate 25 supplies are processed.
The etching, transporting, chamber cleaning and conditioning steps are then repeated. This way
The etching process stage is delayed or slow by the cleaning process stage
Since the process is not performed, the throughput of the process is improved.

In yet another case, during activation of the cleaning gas, the outlet valve 225 from the remote chamber is in a closed position. When the etched substrate 25 is removed or transported from the etching chamber 30, the robot controller 259 opens an outlet valve 225 in the gas line 170 to clean and condition the surface inside the etching chamber. Then, a first signal is transmitted to instruct the active gas to flow into the etching chamber 30 for a short time. Next, when bringing the second substrate 25 to be inserted into the etching chamber 30, the robot control device 259
And a second trigger signal for closing is transmitted. Thereafter, another substrate 25 is placed in the chamber 3
And the etching, transporting, chamber cleaning and conditioning steps are repeated.

In yet another aspect of the present invention, a low gas pressure associated with remote chamber 40 is maintained within etch chamber 30. This aspect of the invention provides a cleaning gas injection nozzle 235 near or at a portion of the chamber having a thick etchant residue to provide cleaning gas injection near the particular chamber surface where more aggressive cleaning is required. It can be used with the specialized gas distributor structure described above to direct the flow. It is believed that maintaining the different pressures between the two chambers causes the active cleaning gas to flow into the process chamber more rapidly, causing the cleaning gas to collide with and clean the chamber surface at high speed. In this process,
The internal volume of the etching chamber 30 is maintained at a higher pressure than that of the remote chamber 40. In this manner, the etching chamber 30 is preferably maintained at a lower pressure than the remote chamber 40. Etching chamber 30 is 0.1 to 80 mTo
Preferably, at a pressure of rr, the remote chamber 40 is maintained at a pressure of about 500 to about 3000 mTorr.

In another aspect of the invention, cleaning and conditioning chamber surfaces, such as ceramic surfaces, which are highly responsive to etching residues, for treatment of the chamber surfaces and attenuation of the concentration of etching residues. Useful multi-cycle cleaning process. In the first stage, a first active cleaning gas is formed by maintaining a gas activator 175, such as a microwave generator 185, at a first power level. In at least one second stage, the second active cleaning gas is formed by maintaining the gas activator 175 at a second power level lower than the first power level.
Due to the higher first power level of the first cleaning step, the active cleaning gas is capable of removing hard etching residues thickly adhered to the chamber walls 45, 50, 55 and components near the substrate 25, the decomposition and Provides highly reactive species. The cleaning gas in the second cleaning stage is activated at lower power levels to provide for efficient processing and conditioning of a surface, such as a ceramic surface, to provide optimal etching conditions within the chamber 30. The first power level is at least about 50
Preferably, the power level is 0 W, preferably about 500 to about 3000 W, and the second power level is at least 1000 W, preferably about 1500 to about 4000 W. The multiple power level process is repeated a sufficient number of times to treat the walls of the chamber to attenuate the concentration of the etch residue in the chamber 30 to a desired level. This number generally ranges from about 1 to about 1 from one cycle.
Up to the range of 0 cycles. The duration of each washing step is from about 0.5 to about 100 seconds, more preferably from about 2 to about 30 seconds.

The chamber processing process of the present invention maximizes the chemical reaction between the active cleaning gas and the etching residue in the chamber 30 and minimizes the reactivity of the cleaning gas with the exposed surface in the etching chamber 30. It is advantageous to This cleaning process was invented to remove etch residues uniformly, regardless of their thickness or stoichiometry. Conventional cleaning processes, particularly those performed by technicians, have not been able to uniformly clean and remove etch residue deposits formed on chamber surfaces. The deposition of the etchant deposits on the chamber surface causes the etchant deposits to be peeled off and the substrate 25 to be etched in the chamber.
Will be contaminated. Uniform removal of etch residues over substantially the entire surface of the chamber minimizes such contamination and yield loss from the substrate 25.

With an active cleaning gas, corrosion damage to the chamber can be significantly reduced compared to the in-situ plasma cleaning step. This is because the energy level of the plasma is reduced in the etching chamber. This has been difficult to achieve in the prior art, which again uses a high power plasma to remove residual deposits caused by extensive corrosion of chamber surfaces and components.
By eliminating the need to replace chamber components, the operating costs of the etching chamber 30 and the cost per substrate 25 can be significantly reduced. Furthermore, rather than interrupting processing within chamber 30 and wet cleaning the chamber walls and components, substrate 25 is preferably etched during substrate 25, and preferably between etching chamber 30 and the loading chamber.
During transport of the wafer, an active cleaning gas can be used to effectively clean the etching chamber 30 in-situ, thereby increasing the etching throughput,
The cost per substrate can be further reduced. The cleaning process is believed to extend the life of the chamber for at least two reasons, and is also believed to increase substrate yield by reducing the deposition of residual by-products that fall off on the substrate.

The treatment and cleaning process removes chemically deposited etchant deposits from the active surfaces of chamber 30 and restores the original chemical reactions and surface functional groups of these surfaces. The treatment and cleaning process may further comprise a ceramic surface such as containing at least one of aluminum nitride, boron carbide, boron nitride, diamond, silicon oxide, silicon carbide, silicon nitride, titanium oxide, titanium carbide, yttrium oxide, zirconium oxide. It is particularly useful for cleaning etch residues that have adhered to, or have undergone a chemical reaction with, the substrate. Active cleaning gases are effective in treating and reconditioning these ceramic surfaces to provide surface stoichiometry and surface functional groups that are chemically consistent with the etching process. Wet cleaning or RIE in chamber 30 due to the conditioned ceramic surface
More reproducible etching characteristics, such as a cleaning process, are obtained. It is highly desirable to implement a significantly improved etch process reproducibility in chamber 30.

Although the present invention has been described with reference to particular preferred embodiments thereof, other embodiments are possible. As will be apparent to those skilled in the art, for example, the processing and cleaning processes of the present invention can be used to process chambers for other applications. Also, as will be apparent to those skilled in the art, the process can be used alone or in combination with other cleaning processes, for example, for processing of a sputtering, ion implantation, or deposition chamber. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions set forth herein.

[Brief description of the drawings]

FIG. 1 is a partial schematic side view of an etching apparatus of the present invention.

FIG. 2 is a flow chart of the process steps used to etch a substrate and to clean and condition the surface walls of an etching apparatus.

FIG. 3 is a partial schematic side view showing another version of the etching apparatus of the present invention.

FIG. 4 is a partial schematic side view showing another version of the etching apparatus of the present invention.

FIG. 5 is a partial schematic side view showing another version of the etching apparatus of the present invention.

FIG. 6 is a partial schematic side view showing another version of the etching apparatus of the present invention.

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Kian, Curie United States, California, Milpitas, Rose Drive 230 (72) Inventor, Lihei, Patrick, El United States of America, California, San Jose, Parkside Avenue 1715 (72) Inventor Morne, Jonathan, D. United States, California, Saratoga, Paseo Presada 13179 (72) Inventor Chou, Waitin United States of America, California, Fremont, Vivienne Place 35875 (72) Inventor Chen, Arthur, W. Bodega Court, Fremont, CA, United States of America, United States 744 United States, California, San Jose, California, San Jose, Spring Park Circle 361 F-term (reference) 4K030 BA29 CA04 DA06 FA04 KA46 5F004 AA15 BA20 BB13 BB14 BB29 BC06 CA02 DA00 DA01 DA02 DA05 DA17 DA18 [Continued from Summary] It is particularly useful when washing objects.

Claims (38)

[Claims] 1. A method for cleaning etching residues from walls and components of an etching chamber, the method comprising: (a) introducing a cleaning gas into a remote chamber near the etching chamber; Activating the cleaning gas in the remote chamber to form an active cleaning gas; and (c) introducing the active cleaning gas into the etching chamber, wherein the cleaning gas is on the walls and components of the etching chamber. Cleaning the etching residue. 2. The method of claim 1, wherein the etching residue contains polymerized and silicon-containing species.
And wherein the active cleaning gas has a volume of about 40,000 cm in the etching chamber. ^Three Flow rate equivalent to about 200 to about 2000 sccm_RAnd about 0
. The method of claim 1, wherein the method is introduced for a period of from 5 to about 100 seconds. 3. The method of claim 1, wherein said active cleaning gas is provided in said etching chamber for about 0.5 times.
The method of claim 1, wherein the method is introduced for about 24 seconds. 4. The method of claim 2, wherein the cleaning gas is activated by microwaves applied to the remote chamber by a microwave plasma generator operating at a power level of about 500 to about 4000 W. The method described in. 5. The method of claim 1, wherein said etching chamber is maintained at a lower pressure than said remote chamber. 6. The method of claim 1, wherein the etching chamber is about 0.1 to about 80 mTorr.
And the remote chamber is maintained at about 500 to about 3000 mTorr.
The method according to claim 8, wherein the pressure is maintained at 7. The cleaning gas comprises NF ₃ , CF ₄ , SF ₆ , C ₂ F ₆ , CCl ₄ ,
C ₂ Cl _6, and characterized in that it is selected from the group consisting of mixtures thereof, The method of claim 1. 8. The method of claim 1, wherein the surface in the etching chamber is one of aluminum nitride, boron carbide, boron nitride, diamond, silicon oxide, silicon carbide, silicon nitride, titanium oxide, titanium carbide, yttrium oxide, and zirconium oxide. The method of claim 1, comprising: 9. A method for etching a silicon-containing layer on a substrate in the etching chamber, the method comprising: (a) introducing a process gas including a silicon etching gas into the etching chamber. (B) applying an RF current at a source power level to an inductor coil near the chamber at a source power level, and applying a RF frequency at a bias power level to a process electrode in the chamber to generate etching plasma from the process gas. Forming, wherein said power ratio P _{r of} said source power level to said bias power level is less than about 20: 1, whereby etching residues on said walls and components of said chamber are formed. While attenuating the formation of Rapidly etched Con-containing layer, wherein the performed by the steps, the method according to claim 1. 10. A method for etching a substrate in an etching chamber and treating and conditioning walls and surfaces of components in the etching chamber, the method comprising: (a) etching the substrate in the etching chamber. and, thereby depositing a etch residues on the surface of the walls and components in the etch chamber, while conveying the (b) the substrate out of the chamber, at the same time, activity cleaning of high flow rate F _R Introducing a jet of gas into the etching chamber for a time sufficient to treat and condition the surface of the etching chamber without substantially corroding the surface. 11. In step (b), the active cleaning gas has a volume of about 40,
000cm from about 200 to the chamber ³ to about 2000sccm equivalent flow rate F _R, period of from about 0.5 to about 100 seconds, and wherein the Rukoto introduced into the etch chamber, according to claim 10 the method of. 12. The method according to claim 1, wherein said active cleaning gas is provided in said etching chamber at a pressure of about 0.1 mm.
12. The method of claim 11, wherein said method is introduced for a time between 5 and about 24 seconds. 13. The cleaning gas of claim 10, wherein the cleaning gas is activated by microwaves applied to the remote chamber by a microwave plasma generator operating at a power level of about 500 to about 4000 W. The method described in. 14. The method of claim 1, wherein the etching chamber is maintained at a higher pressure than the remote chamber. 15. The method as recited in claim 15, wherein said etching chamber is about 0.1 to about 80 mTorr.
r and the remote chamber is about 500 to about 3000 mTorr
The method according to claim 14, wherein the pressure is maintained at r. 16. The method of claim 1, wherein the surface in the etching chamber is one of aluminum nitride, boron carbide, boron nitride, diamond, silicon oxide, silicon carbide, silicon nitride, titanium oxide, titanium carbide, yttrium oxide, and zirconium oxide. The method of claim 11, comprising: 17. A method of processing the etching chamber to remove etching residues from walls and components of the etching chamber, the method comprising: spraying an active cleaning gas into the etching chamber; 000
introducing at a flow rate F _R at least equal to about 200 to about 2000 sccm for a cm ³ etch chamber for about 0.5 to about 100 seconds to substantially corrode the walls and components of the chamber. Cleaning the etching residue without the need for cleaning. 18. The method as recited in claim 18, wherein said active cleaning gas is provided in said etching chamber at a pressure of about 0.1 mm.
18. The method according to claim 17, wherein said method is introduced for a period of from 5 to about 24 seconds. 19. The cleaning gas is activated by microwaves applied into the remote chamber by a microwave plasma generator operating at a power level of about 500 to about 4000W. 18. The method according to 17. 20. The method of claim 17, wherein the etching chamber is maintained at a higher pressure than the remote chamber. 21. The method of claim 19, wherein the etching chamber is about 0.1 to about 80 mTorr.
r and the remote chamber is about 500 to about 3000 mTorr
21. The method according to claim 20, wherein the pressure is maintained at r. 22. The method of claim 19, wherein the surface in the etching chamber is one of aluminum nitride, boron carbide, boron nitride, diamond, silicon oxide, silicon carbide, silicon nitride, titanium oxide, titanium carbide, yttrium oxide, zirconium oxide. The method according to claim 17, comprising: 23. A method of treating an etching chamber to remove etching residues from walls and components of the etching chamber, the method comprising:
The method comprises: (a) introducing a first active cleaning gas formed by maintaining a gas activator in a remote chamber at a first power level into the etching chamber in a first step; (b) ) A second active cleaning gas formed by maintaining the gas activator in the remote chamber at a second power level different from the first power level into the etching chamber in at least one second stage; And introducing. 24. The method of claim 23, wherein each of the first and second steps is performed for a period of about 0.5 to about 100 seconds. 25. The power level applied to the microwave generator in the first stage is at least about 2000W, and the power level applied to the microwave generator in the second stage is less than about 1000W. A method according to claim 23, characterized in that: 26. In one or both of the steps, the active cleaning gas is introduced into the etching chamber at a flow rate F _R equal to about 200 to about 2000 sccm for a chamber having a volume of about 40,000 cm ^3. The method according to claim 23, wherein the method is performed. 27. The method of claim 27, wherein the etching chamber is about 0.1 to about 80 mTorr.
r and the remote chamber is about 500 to about 3000 mTorr
24. The method according to claim 23, wherein the pressure is maintained at r. 28. The method of claim 28, wherein the surface in the etching chamber is one of aluminum nitride, boron carbide, boron nitride, diamond, silicon oxide, silicon carbide, silicon nitride, titanium oxide, titanium carbide, yttrium oxide, zirconium oxide. 24. The method of claim 23, comprising: 29. An apparatus for etching a substrate, the apparatus comprising: (a) a process gas inlet for introducing a process gas into an etching chamber;
An etching chamber having a plasma generator for forming plasma from the process gas for etching a substrate, and an exhaust system for exhausting a consumed process gas from the etching chamber; and (b) forming an active cleaning gas inside. (C) a gas distribution system, the gas distribution system including: (i) a gas line for conveying the active cleaning gas from the remote chamber to the etching chamber; (Ii) a gas flow distributor that directs the flow of the active cleaning gas substantially parallel and adjacent to one or more interior surfaces of the chamber; and (iii) into the gas flow distributor. A gas flow conditioner that regulates the flow of the active cleaning gas. 30. The gas flow distributor includes a plurality of gas injection nozzles having a thick layer of etching residue within the etching chamber and positioned adjacent a portion of the surface of the chamber. The device according to claim 29, characterized in that: 31. The apparatus of claim 29, wherein the gas flow distributor has a plurality of gas injection nozzles symmetrically disposed about a central axis of the chamber. 32. The apparatus of claim 29, wherein the gas flow injection nozzle is located behind a plate parallel to a surface of the chamber. 33. The gas flow distributor includes one or more gas injection nozzles terminating in a channel in the chamber, the channel having an elongated annular shape covering at least a portion of the channel. 30. The device according to claim 29, comprising a ledge. 34. A method of using the apparatus of claim 29 to etch a substrate, the method comprising: (1) etching the substrate in the etching chamber; Removing the substrate from the chamber; and (3) cleaning and conditioning the chamber during or after step (2) by introducing an active cleaning gas into the etching chamber using the gas flow distribution system. The steps of: 35. An apparatus for etching a substrate, the apparatus comprising: (a) a process gas inlet for introducing a process gas into an etching chamber; and a plasma for forming a plasma from the process gas to etch the substrate. An etching chamber including a generator and an exhaust system for exhausting consumed process gas from the etching chamber; (b) a remote chamber adjacent to the etching chamber for forming an active cleaning gas therein; and (c) a gas. A distribution system, the gas distribution system comprising: (i) a gas line for carrying the active cleaning gas from the remote chamber to the etching chamber; and (ii) a thick etch deposition layer. A nozzle disposed adjacent to the It has, without corroding a portion of the chamber, and a gas flow distributor to direct the scope of these the flow of the active cleaning gas to preferentially remove the thicker etch the deposited layer, device. 36. The apparatus of claim 35, wherein the gas flow distributor has a plurality of gas injection nozzles symmetrically disposed about a central axis of the chamber. 37. The apparatus of claim 35, wherein the gas flow injection nozzle is located behind a plate parallel to a surface of the chamber. 38. The gas flow distributor includes one or more gas injection nozzles terminating in a channel in the chamber, the channel having an elongated annular shape covering at least a portion of the channel. 36. The device of claim 35, comprising a ledge.